#include<bits/stdc++.h>
#pragma GCC optimize("Ofast,unroll-loops")
#pragma GCC target("avx,avx2,sse,sse2,sse3,fma")
using namespace std;
#define ll long long
#define fi first
#define se second
#define pb emplace_back
#define all(n) (n).begin(),(n).end()
#define mem(n,x) memset(n,x,sizeof(n))
#define IOS ios::sync_with_stdio(0),cin.tie(0)
#define pii pair<ll,ll>
#define vi vector<ll>
#define dbg(...) cerr<<#__VA_ARGS__<<" = ";_do(__VA_ARGS__);
template<typename A> void _do(A x){ cerr<<x<<"\n"; }
template<typename A, typename ...B> void _do(A x, B ...y){ cerr<<x<<", "; _do(y...);}

int n;
vi cans, cur;
bitset<75> cover[75];
bool E[75][75];
vi v(75);

void init(){
	for(int i=0;i<n;i++) cover[i].reset();
	for(int i=0;i<n;i++) for(int j=0;j<n;j++) E[i][j] = 0;
	cans.clear(); cur.clear();
	for(int i=0;i<n;i++) v[i] = 0;
}

void dfs(int num, int cur, bitset<75> b){
	/* for(auto i:v) cout<<i<<" "; cout<<'\n'; */
	if((int)b.count() == n){
		/* dbg(num, cur, b.count(), v.size()); */
		if(num < (int)cans.size() || cans.empty()){ 
			cans.resize(num);
			for(int i=0;i<num;i++) cans[i] = v[i];
		}
		return;
	}
	if(num == 5) return;
	for(int i=cur;i<n;i++){
		v[num] = i;
		dfs(num+1, i+1, b | cover[i]);
	}
}

void solve(){
	char c;
	for(int i=0;i<n;i++) for(int j=0;j<n;j++) cin>>c, E[i][j] = c-'0';
	for(int i=0;i<n;i++){
		for(int j=0;j<n;j++){
			if(i==j || E[i][j]) cover[i][j] = 1;
		}
	}
	bitset<75> b;
	dfs(0, 0, b);
	cout<<cans.size()<<" ";
	for(auto &i:cans) cout<<i+1<<" ";
	cout<<'\n';
}

signed main(){
	IOS;
	int kas = 0;
	while(cin>>n){
		init();
		cout<<"Case "<<++kas<<": ";
		solve();
	}

}